The Polycomb and Trithorax system plays an important role in the maintenance of gene expression states by means of epigenetic memory. In this system, the Polycomb group (PcG) and Trithorax group (TrxG) proteins act antagonistically via Polycomb and Trithorax response elements (PRE/TREs), which are bistable, switchable elements that are able to maintain both silent and active gene expression states according to the activity of their associated gene. In flies, PRE/TREs are well characterised, consisting of multiple short DNA sequence motifs that are recognised by site-specific DNA proteins which recruit PcG or TrxG proteins. One of those DNA sequence motifs is the GTGT motif which consists of several repeats of the dinucleotide GT and has been found to be enriched in fly PRE/TREs by a computational motif discovery. The GTGT motif enables the direct binding of specific DNA binding proteins that recruit PcG or TrxG proteins. Moreover, it may also modulate the properties of noncoding RNAs into which many PRE/TREs are transcribed. In my project, I aim to investigate the role of the GTGT motif in fly PRE/TREs and to determine whether it functions by modulating the levels or properties of noncoding RNAs by working on the vestigial PRE/TRE in Drosophila.
Publications
Reinig, J., Ruge, F., Howard, M., Ringrose, L. (2020). A theoretical model of Polycomb/Trithorax action unites stable epigenetic memory and dynamic regulation. Nature communications. (Article)